N-oleoylethanolamide treatment of lymphoblasts deficient in Tafazzin improves cell growth and mitochondrial morphology and dynamics

Abstract

Barth syndrome (BTHS) is caused by mutations in the TAZ gene encoding the cardiolipin remodeling enzyme, Tafazzin. The study objective was to quantitatively examine growth characteristics and mitochondrial morphology of transformed lymphoblast cell lines derived from five patients with BTHS relative to five healthy controls, as well as the therapeutic potential of oleoylethanolamide (OEA) and linoleoylethanolamide (LEA). These bioactive lipids both activate PPARα, which may be therapeutic. BTHS lymphoblasts grew more slowly than controls, suggesting lymphopenia merits clinical investigation. Treatment of BTHS lymphoblasts with OEA, but not LEA, significantly restored mitochondrial membrane potential, as well as colony growth in all BTHS lymphoblast lines, although a full growth rescue was not achieved. Quantification analysis of electron micrographs from three BTHS and healthy lymphoblast donors indicated similar numbers of mitochondria per cell, but lower average cristae length per mitochondrion, and higher mitochondrial density. Additionally, BTHS lymphoblasts had larger mitochondria, and a higher percentage of abnormally large mitochondria (> 1 μm2) than healthy controls. Notably, OEA treatment significantly restored mitochondrial size, without affecting density or cristae lengths. Cardiolipin total content, relative linoleic acid content and monolysocardiolipin:cardiolipin ratios were not improved by OEA, indicating that effects on growth, and mitochondrial morphology and function, occurred without resolving this deficit. However, immunoblotting showed higher levels of OPA1, a biomarker for mitochondrial fusion, in BTHS lymphoblasts, which was attenuated by OEA treatment, implicating altered mitochondrial dynamics in the pathology and treatment of BTHS.

Phenotypic Characterization of Female Carrier Mice Heterozygous for Tafazzin Deletion

“…The organic phase was carefully collected and desiccated under a stream of nitrogen gas. To separate the individual phospholipid species, the organic phase was resuspended in chloroform and applied onto Silica Gel HF plates measuring 20 cm × 20 cm with a layer thickness of 250 μM (Analtech Inc., Cole-Parmer Canada, Montreal, QC, Canada), and resolved using thin-layer chromatography with a solvent system of chloroform:methanol:2-propanol:0.25% KCl:trimethylamine (30:9:25:6:18, v / v/v / v/v ) [ 26 ]. Cardiolipin bands were detected using UV illumination after spraying with 0.1% 2,7-dichlorofuorescin in methanol ( w / v ) and scrapped in reference to known cardiolipin standards (Avanti Polar Lipids, Millipore Sigma, Mississauga, ON, Canada).…”

Recent advances and new perspectives in mitochondrial dysfunction

“…Surprisingly, both studies provided new evidence to support that cardiolipin remodeling may not be required to improve mitochondrial function in this syndrome. One study 9 showed that N- oleoyl-ethanolamide treatment significantly improved mitochondrial morphology and function of BTHS lymphoblasts, possibly by affecting mitochondrial dynamics without resolving cardiolipin alterations. The other one 10 reported that SS-31 peptide improved mitochondrial respiratory capacity and promoted supercomplex organization in a BTHS animal model without affecting altered cardiolipin remodeling.…”